Widespread use is being made of disk-like piezoelectric tone transducers in devices which produce an audible tone in response to an electrical signal. Such devices are used, for example, in automotive warning circuits, in smoke detectors, and in instruction devices, and are usually mounted on the circuit board on which the control circuitry for the device is mounted. Mounting means for transducers of this type commonly comprise a plastic housing which supports the transducer and which contains electrical contacting devices which electrically contact the transducer at a location adjacent to its periphery and on the ceramic piezoelectric material which is located inwardly from the periphery of the transducer. The present invention is directed to the achievement of a supporting and contacting device for a transducer which does not require insulating housing and which can be easily assembled to the circuit board on which the transducer is to be mounted.
In accordance with the principles of the invention, a pair of spaced-apart sheet metal transducer supporting members are mounted on the circuit board for supporting the transducer around its periphery and a spring contact member is mounted on the circuit board between the supporting members for contacting the ceramic piezoelectric material which is centrally supported on the transducer. The supporting members are disposed in planes which extend normally of the circuit board on which they are mounted and each supporting member has opposed re-entrant notches adjacent to its ends so that the disk-like transducer can be positioned on the two supporting members with its edge received in the four notches of the two supporting members. The engagement of the edges of the transducer with the notches in the supporting member provides the electrical contact required with the periphery of the transducer and the spring contact member is resiliently biased against the piezoelectric material of the transducer when it is mounted in the supporting members.
Supporting and contacting members, in accordance with the invention, can be produced in the form of a one-piece device of stamped and formed sheet metal which can be assembled to the circuit board by simply positioning it on the board with solder tabs, which are integral with the device, extending through holes in the circuit board. The solder tabs are soldered to conductors on the circuit board to establish electrical connections required for the driving circuit. Alternatively, the supporting members and the contact member can be produced as loose piece items and can be separately assembled to the circuit board.